21030101 has 4 divisors (see below), whose sum is σ = 21226752. Its totient is φ = 20833452.

The previous prime is 21030083. The next prime is 21030109. The reversal of 21030101 is 10103012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21030101 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98165 + ... + 98378.

It is an arithmetic number, because the mean of its divisors is an integer number (5306688).

Almost surely, 2^21030101 is an apocalyptic number.

It is an amenable number.

21030101 is a deficient number, since it is larger than the sum of its proper divisors (196651).

21030101 is a wasteful number, since it uses less digits than its factorization.

21030101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196650.

The product of its (nonzero) digits is 6, while the sum is 8.

The square root of 21030101 is about 4585.8588072465. The cubic root of 21030101 is about 276.0241743511.

Adding to 21030101 its reverse (10103012), we get a palindrome (31133113).

The spelling of 21030101 in words is "twenty-one million, thirty thousand, one hundred one".